1 // SPDX-License-Identifier: GPL-2.0
3 #include <linux/blkdev.h>
4 #include <linux/iversion.h>
5 #include "compression.h"
7 #include "delalloc-space.h"
9 #include "transaction.h"
12 #define BTRFS_MAX_DEDUPE_LEN SZ_16M
14 static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
21 struct btrfs_root *root = BTRFS_I(inode)->root;
24 inode_inc_iversion(inode);
26 inode->i_mtime = inode->i_ctime = current_time(inode);
28 * We round up to the block size at eof when determining which
29 * extents to clone above, but shouldn't round up the file size.
31 if (endoff > destoff + olen)
32 endoff = destoff + olen;
33 if (endoff > inode->i_size) {
34 i_size_write(inode, endoff);
35 btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
38 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
40 btrfs_abort_transaction(trans, ret);
41 btrfs_end_transaction(trans);
44 ret = btrfs_end_transaction(trans);
49 static int copy_inline_to_page(struct btrfs_inode *inode,
50 const u64 file_offset,
56 struct btrfs_fs_info *fs_info = inode->root->fs_info;
57 const u32 block_size = fs_info->sectorsize;
58 const u64 range_end = file_offset + block_size - 1;
59 const size_t inline_size = size - btrfs_file_extent_calc_inline_size(0);
60 char *data_start = inline_data + btrfs_file_extent_calc_inline_size(0);
61 struct extent_changeset *data_reserved = NULL;
62 struct page *page = NULL;
63 struct address_space *mapping = inode->vfs_inode.i_mapping;
66 ASSERT(IS_ALIGNED(file_offset, block_size));
69 * We have flushed and locked the ranges of the source and destination
70 * inodes, we also have locked the inodes, so we are safe to do a
71 * reservation here. Also we must not do the reservation while holding
72 * a transaction open, otherwise we would deadlock.
74 ret = btrfs_delalloc_reserve_space(inode, &data_reserved, file_offset,
79 page = find_or_create_page(mapping, file_offset >> PAGE_SHIFT,
80 btrfs_alloc_write_mask(mapping));
86 ret = set_page_extent_mapped(page);
90 clear_extent_bit(&inode->io_tree, file_offset, range_end,
91 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
93 ret = btrfs_set_extent_delalloc(inode, file_offset, range_end, 0, NULL);
98 * After dirtying the page our caller will need to start a transaction,
99 * and if we are low on metadata free space, that can cause flushing of
100 * delalloc for all inodes in order to get metadata space released.
101 * However we are holding the range locked for the whole duration of
102 * the clone/dedupe operation, so we may deadlock if that happens and no
103 * other task releases enough space. So mark this inode as not being
104 * possible to flush to avoid such deadlock. We will clear that flag
105 * when we finish cloning all extents, since a transaction is started
106 * after finding each extent to clone.
108 set_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &inode->runtime_flags);
110 if (comp_type == BTRFS_COMPRESS_NONE) {
111 memcpy_to_page(page, offset_in_page(file_offset), data_start,
113 flush_dcache_page(page);
115 ret = btrfs_decompress(comp_type, data_start, page,
116 offset_in_page(file_offset),
120 flush_dcache_page(page);
124 * If our inline data is smaller then the block/page size, then the
125 * remaining of the block/page is equivalent to zeroes. We had something
126 * like the following done:
128 * $ xfs_io -f -c "pwrite -S 0xab 0 500" file
129 * $ sync # (or fsync)
130 * $ xfs_io -c "falloc 0 4K" file
131 * $ xfs_io -c "pwrite -S 0xcd 4K 4K"
133 * So what's in the range [500, 4095] corresponds to zeroes.
135 if (datal < block_size) {
136 memzero_page(page, datal, block_size - datal);
137 flush_dcache_page(page);
140 btrfs_page_set_uptodate(fs_info, page, file_offset, block_size);
141 btrfs_page_clear_checked(fs_info, page, file_offset, block_size);
142 btrfs_page_set_dirty(fs_info, page, file_offset, block_size);
149 btrfs_delalloc_release_space(inode, data_reserved, file_offset,
151 btrfs_delalloc_release_extents(inode, block_size);
153 extent_changeset_free(data_reserved);
159 * Deal with cloning of inline extents. We try to copy the inline extent from
160 * the source inode to destination inode when possible. When not possible we
161 * copy the inline extent's data into the respective page of the inode.
163 static int clone_copy_inline_extent(struct inode *dst,
164 struct btrfs_path *path,
165 struct btrfs_key *new_key,
166 const u64 drop_start,
171 struct btrfs_trans_handle **trans_out)
173 struct btrfs_fs_info *fs_info = btrfs_sb(dst->i_sb);
174 struct btrfs_root *root = BTRFS_I(dst)->root;
175 const u64 aligned_end = ALIGN(new_key->offset + datal,
176 fs_info->sectorsize);
177 struct btrfs_trans_handle *trans = NULL;
178 struct btrfs_drop_extents_args drop_args = { 0 };
180 struct btrfs_key key;
182 if (new_key->offset > 0) {
183 ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
184 inline_data, size, datal, comp_type);
188 key.objectid = btrfs_ino(BTRFS_I(dst));
189 key.type = BTRFS_EXTENT_DATA_KEY;
191 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
194 } else if (ret > 0) {
195 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
196 ret = btrfs_next_leaf(root, path);
200 goto copy_inline_extent;
202 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
203 if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
204 key.type == BTRFS_EXTENT_DATA_KEY) {
206 * There's an implicit hole at file offset 0, copy the
207 * inline extent's data to the page.
209 ASSERT(key.offset > 0);
212 } else if (i_size_read(dst) <= datal) {
213 struct btrfs_file_extent_item *ei;
215 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
216 struct btrfs_file_extent_item);
218 * If it's an inline extent replace it with the source inline
219 * extent, otherwise copy the source inline extent data into
220 * the respective page at the destination inode.
222 if (btrfs_file_extent_type(path->nodes[0], ei) ==
223 BTRFS_FILE_EXTENT_INLINE)
224 goto copy_inline_extent;
231 * We have no extent items, or we have an extent at offset 0 which may
232 * or may not be inlined. All these cases are dealt the same way.
234 if (i_size_read(dst) > datal) {
236 * At the destination offset 0 we have either a hole, a regular
237 * extent or an inline extent larger then the one we want to
238 * clone. Deal with all these cases by copying the inline extent
239 * data into the respective page at the destination inode.
245 * Release path before starting a new transaction so we don't hold locks
246 * that would confuse lockdep.
248 btrfs_release_path(path);
250 * If we end up here it means were copy the inline extent into a leaf
251 * of the destination inode. We know we will drop or adjust at most one
252 * extent item in the destination root.
254 * 1 unit - adjusting old extent (we may have to split it)
255 * 1 unit - add new extent
256 * 1 unit - inode update
258 trans = btrfs_start_transaction(root, 3);
260 ret = PTR_ERR(trans);
264 drop_args.path = path;
265 drop_args.start = drop_start;
266 drop_args.end = aligned_end;
267 drop_args.drop_cache = true;
268 ret = btrfs_drop_extents(trans, root, BTRFS_I(dst), &drop_args);
271 ret = btrfs_insert_empty_item(trans, root, path, new_key, size);
275 write_extent_buffer(path->nodes[0], inline_data,
276 btrfs_item_ptr_offset(path->nodes[0],
279 btrfs_update_inode_bytes(BTRFS_I(dst), datal, drop_args.bytes_found);
280 btrfs_set_inode_full_sync(BTRFS_I(dst));
281 ret = btrfs_inode_set_file_extent_range(BTRFS_I(dst), 0, aligned_end);
283 if (!ret && !trans) {
285 * No transaction here means we copied the inline extent into a
286 * page of the destination inode.
288 * 1 unit to update inode item
290 trans = btrfs_start_transaction(root, 1);
292 ret = PTR_ERR(trans);
297 btrfs_abort_transaction(trans, ret);
298 btrfs_end_transaction(trans);
307 * Release our path because we don't need it anymore and also because
308 * copy_inline_to_page() needs to reserve data and metadata, which may
309 * need to flush delalloc when we are low on available space and
310 * therefore cause a deadlock if writeback of an inline extent needs to
311 * write to the same leaf or an ordered extent completion needs to write
314 btrfs_release_path(path);
316 ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,
317 inline_data, size, datal, comp_type);
322 * btrfs_clone() - clone a range from inode file to another
324 * @src: Inode to clone from
325 * @inode: Inode to clone to
326 * @off: Offset within source to start clone from
327 * @olen: Original length, passed by user, of range to clone
328 * @olen_aligned: Block-aligned value of olen
329 * @destoff: Offset within @inode to start clone
330 * @no_time_update: Whether to update mtime/ctime on the target inode
332 static int btrfs_clone(struct inode *src, struct inode *inode,
333 const u64 off, const u64 olen, const u64 olen_aligned,
334 const u64 destoff, int no_time_update)
336 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
337 struct btrfs_path *path = NULL;
338 struct extent_buffer *leaf;
339 struct btrfs_trans_handle *trans;
341 struct btrfs_key key;
345 const u64 len = olen_aligned;
346 u64 last_dest_end = destoff;
349 buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
353 path = btrfs_alloc_path();
359 path->reada = READA_FORWARD;
361 key.objectid = btrfs_ino(BTRFS_I(src));
362 key.type = BTRFS_EXTENT_DATA_KEY;
366 u64 next_key_min_offset = key.offset + 1;
367 struct btrfs_file_extent_item *extent;
371 struct btrfs_key new_key;
372 u64 disko = 0, diskl = 0;
373 u64 datao = 0, datal = 0;
377 /* Note the key will change type as we walk through the tree */
378 ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
383 * First search, if no extent item that starts at offset off was
384 * found but the previous item is an extent item, it's possible
385 * it might overlap our target range, therefore process it.
387 if (key.offset == off && ret > 0 && path->slots[0] > 0) {
388 btrfs_item_key_to_cpu(path->nodes[0], &key,
390 if (key.type == BTRFS_EXTENT_DATA_KEY)
394 nritems = btrfs_header_nritems(path->nodes[0]);
396 if (path->slots[0] >= nritems) {
397 ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
402 nritems = btrfs_header_nritems(path->nodes[0]);
404 leaf = path->nodes[0];
405 slot = path->slots[0];
407 btrfs_item_key_to_cpu(leaf, &key, slot);
408 if (key.type > BTRFS_EXTENT_DATA_KEY ||
409 key.objectid != btrfs_ino(BTRFS_I(src)))
412 ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
414 extent = btrfs_item_ptr(leaf, slot,
415 struct btrfs_file_extent_item);
416 extent_gen = btrfs_file_extent_generation(leaf, extent);
417 comp = btrfs_file_extent_compression(leaf, extent);
418 type = btrfs_file_extent_type(leaf, extent);
419 if (type == BTRFS_FILE_EXTENT_REG ||
420 type == BTRFS_FILE_EXTENT_PREALLOC) {
421 disko = btrfs_file_extent_disk_bytenr(leaf, extent);
422 diskl = btrfs_file_extent_disk_num_bytes(leaf, extent);
423 datao = btrfs_file_extent_offset(leaf, extent);
424 datal = btrfs_file_extent_num_bytes(leaf, extent);
425 } else if (type == BTRFS_FILE_EXTENT_INLINE) {
426 /* Take upper bound, may be compressed */
427 datal = btrfs_file_extent_ram_bytes(leaf, extent);
431 * The first search might have left us at an extent item that
432 * ends before our target range's start, can happen if we have
433 * holes and NO_HOLES feature enabled.
435 if (key.offset + datal <= off) {
438 } else if (key.offset >= off + len) {
441 next_key_min_offset = key.offset + datal;
442 size = btrfs_item_size(leaf, slot);
443 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, slot),
446 btrfs_release_path(path);
448 memcpy(&new_key, &key, sizeof(new_key));
449 new_key.objectid = btrfs_ino(BTRFS_I(inode));
450 if (off <= key.offset)
451 new_key.offset = key.offset + destoff - off;
453 new_key.offset = destoff;
456 * Deal with a hole that doesn't have an extent item that
457 * represents it (NO_HOLES feature enabled).
458 * This hole is either in the middle of the cloning range or at
459 * the beginning (fully overlaps it or partially overlaps it).
461 if (new_key.offset != last_dest_end)
462 drop_start = last_dest_end;
464 drop_start = new_key.offset;
466 if (type == BTRFS_FILE_EXTENT_REG ||
467 type == BTRFS_FILE_EXTENT_PREALLOC) {
468 struct btrfs_replace_extent_info clone_info;
471 * a | --- range to clone ---| b
472 * | ------------- extent ------------- |
475 /* Subtract range b */
476 if (key.offset + datal > off + len)
477 datal = off + len - key.offset;
479 /* Subtract range a */
480 if (off > key.offset) {
481 datao += off - key.offset;
482 datal -= off - key.offset;
485 clone_info.disk_offset = disko;
486 clone_info.disk_len = diskl;
487 clone_info.data_offset = datao;
488 clone_info.data_len = datal;
489 clone_info.file_offset = new_key.offset;
490 clone_info.extent_buf = buf;
491 clone_info.is_new_extent = false;
492 ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
493 drop_start, new_key.offset + datal - 1,
494 &clone_info, &trans);
498 ASSERT(type == BTRFS_FILE_EXTENT_INLINE);
500 * Inline extents always have to start at file offset 0
501 * and can never be bigger then the sector size. We can
502 * never clone only parts of an inline extent, since all
503 * reflink operations must start at a sector size aligned
504 * offset, and the length must be aligned too or end at
505 * the i_size (which implies the whole inlined data).
507 ASSERT(key.offset == 0);
508 ASSERT(datal <= fs_info->sectorsize);
509 if (WARN_ON(type != BTRFS_FILE_EXTENT_INLINE) ||
510 WARN_ON(key.offset != 0) ||
511 WARN_ON(datal > fs_info->sectorsize)) {
516 ret = clone_copy_inline_extent(inode, path, &new_key,
517 drop_start, datal, size,
523 btrfs_release_path(path);
526 * Whenever we share an extent we update the last_reflink_trans
527 * of each inode to the current transaction. This is needed to
528 * make sure fsync does not log multiple checksum items with
529 * overlapping ranges (because some extent items might refer
530 * only to sections of the original extent). For the destination
531 * inode we do this regardless of the generation of the extents
532 * or even if they are inline extents or explicit holes, to make
533 * sure a full fsync does not skip them. For the source inode,
534 * we only need to update last_reflink_trans in case it's a new
535 * extent that is not a hole or an inline extent, to deal with
536 * the checksums problem on fsync.
538 if (extent_gen == trans->transid && disko > 0)
539 BTRFS_I(src)->last_reflink_trans = trans->transid;
541 BTRFS_I(inode)->last_reflink_trans = trans->transid;
543 last_dest_end = ALIGN(new_key.offset + datal,
544 fs_info->sectorsize);
545 ret = clone_finish_inode_update(trans, inode, last_dest_end,
546 destoff, olen, no_time_update);
549 if (new_key.offset + datal >= destoff + len)
552 btrfs_release_path(path);
553 key.offset = next_key_min_offset;
555 if (fatal_signal_pending(current)) {
564 if (last_dest_end < destoff + len) {
566 * We have an implicit hole that fully or partially overlaps our
567 * cloning range at its end. This means that we either have the
568 * NO_HOLES feature enabled or the implicit hole happened due to
569 * mixing buffered and direct IO writes against this file.
571 btrfs_release_path(path);
574 * When using NO_HOLES and we are cloning a range that covers
575 * only a hole (no extents) into a range beyond the current
576 * i_size, punching a hole in the target range will not create
577 * an extent map defining a hole, because the range starts at or
578 * beyond current i_size. If the file previously had an i_size
579 * greater than the new i_size set by this clone operation, we
580 * need to make sure the next fsync is a full fsync, so that it
581 * detects and logs a hole covering a range from the current
582 * i_size to the new i_size. If the clone range covers extents,
583 * besides a hole, then we know the full sync flag was already
584 * set by previous calls to btrfs_replace_file_extents() that
585 * replaced file extent items.
587 if (last_dest_end >= i_size_read(inode))
588 btrfs_set_inode_full_sync(BTRFS_I(inode));
590 ret = btrfs_replace_file_extents(BTRFS_I(inode), path,
591 last_dest_end, destoff + len - 1, NULL, &trans);
595 ret = clone_finish_inode_update(trans, inode, destoff + len,
596 destoff, olen, no_time_update);
600 btrfs_free_path(path);
602 clear_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &BTRFS_I(inode)->runtime_flags);
607 static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
608 struct inode *inode2, u64 loff2, u64 len)
610 unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
611 unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
614 static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
615 struct inode *inode2, u64 loff2, u64 len)
617 if (inode1 < inode2) {
618 swap(inode1, inode2);
620 } else if (inode1 == inode2 && loff2 < loff1) {
623 lock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
624 lock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
627 static void btrfs_double_mmap_lock(struct inode *inode1, struct inode *inode2)
630 swap(inode1, inode2);
631 down_write(&BTRFS_I(inode1)->i_mmap_lock);
632 down_write_nested(&BTRFS_I(inode2)->i_mmap_lock, SINGLE_DEPTH_NESTING);
635 static void btrfs_double_mmap_unlock(struct inode *inode1, struct inode *inode2)
637 up_write(&BTRFS_I(inode1)->i_mmap_lock);
638 up_write(&BTRFS_I(inode2)->i_mmap_lock);
641 static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 len,
642 struct inode *dst, u64 dst_loff)
644 const u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
648 * Lock destination range to serialize with concurrent readpages() and
649 * source range to serialize with relocation.
651 btrfs_double_extent_lock(src, loff, dst, dst_loff, len);
652 ret = btrfs_clone(src, dst, loff, len, ALIGN(len, bs), dst_loff, 1);
653 btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
658 static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
659 struct inode *dst, u64 dst_loff)
662 u64 i, tail_len, chunk_count;
663 struct btrfs_root *root_dst = BTRFS_I(dst)->root;
665 spin_lock(&root_dst->root_item_lock);
666 if (root_dst->send_in_progress) {
667 btrfs_warn_rl(root_dst->fs_info,
668 "cannot deduplicate to root %llu while send operations are using it (%d in progress)",
669 root_dst->root_key.objectid,
670 root_dst->send_in_progress);
671 spin_unlock(&root_dst->root_item_lock);
674 root_dst->dedupe_in_progress++;
675 spin_unlock(&root_dst->root_item_lock);
677 tail_len = olen % BTRFS_MAX_DEDUPE_LEN;
678 chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);
680 for (i = 0; i < chunk_count; i++) {
681 ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN,
686 loff += BTRFS_MAX_DEDUPE_LEN;
687 dst_loff += BTRFS_MAX_DEDUPE_LEN;
691 ret = btrfs_extent_same_range(src, loff, tail_len, dst, dst_loff);
693 spin_lock(&root_dst->root_item_lock);
694 root_dst->dedupe_in_progress--;
695 spin_unlock(&root_dst->root_item_lock);
700 static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
701 u64 off, u64 olen, u64 destoff)
703 struct inode *inode = file_inode(file);
704 struct inode *src = file_inode(file_src);
705 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
709 u64 bs = fs_info->sb->s_blocksize;
712 * VFS's generic_remap_file_range_prep() protects us from cloning the
713 * eof block into the middle of a file, which would result in corruption
714 * if the file size is not blocksize aligned. So we don't need to check
715 * for that case here.
717 if (off + len == src->i_size)
718 len = ALIGN(src->i_size, bs) - off;
720 if (destoff > inode->i_size) {
721 const u64 wb_start = ALIGN_DOWN(inode->i_size, bs);
723 ret = btrfs_cont_expand(BTRFS_I(inode), inode->i_size, destoff);
727 * We may have truncated the last block if the inode's size is
728 * not sector size aligned, so we need to wait for writeback to
729 * complete before proceeding further, otherwise we can race
730 * with cloning and attempt to increment a reference to an
731 * extent that no longer exists (writeback completed right after
732 * we found the previous extent covering eof and before we
733 * attempted to increment its reference count).
735 ret = btrfs_wait_ordered_range(inode, wb_start,
742 * Lock destination range to serialize with concurrent readpages() and
743 * source range to serialize with relocation.
745 btrfs_double_extent_lock(src, off, inode, destoff, len);
746 ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
747 btrfs_double_extent_unlock(src, off, inode, destoff, len);
750 * We may have copied an inline extent into a page of the destination
751 * range, so wait for writeback to complete before truncating pages
752 * from the page cache. This is a rare case.
754 wb_ret = btrfs_wait_ordered_range(inode, destoff, len);
755 ret = ret ? ret : wb_ret;
757 * Truncate page cache pages so that future reads will see the cloned
758 * data immediately and not the previous data.
760 truncate_inode_pages_range(&inode->i_data,
761 round_down(destoff, PAGE_SIZE),
762 round_up(destoff + len, PAGE_SIZE) - 1);
767 static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in,
768 struct file *file_out, loff_t pos_out,
769 loff_t *len, unsigned int remap_flags)
771 struct inode *inode_in = file_inode(file_in);
772 struct inode *inode_out = file_inode(file_out);
773 u64 bs = BTRFS_I(inode_out)->root->fs_info->sb->s_blocksize;
774 bool same_inode = inode_out == inode_in;
778 if (!(remap_flags & REMAP_FILE_DEDUP)) {
779 struct btrfs_root *root_out = BTRFS_I(inode_out)->root;
781 if (btrfs_root_readonly(root_out))
784 ASSERT(inode_in->i_sb == inode_out->i_sb);
787 /* Don't make the dst file partly checksummed */
788 if ((BTRFS_I(inode_in)->flags & BTRFS_INODE_NODATASUM) !=
789 (BTRFS_I(inode_out)->flags & BTRFS_INODE_NODATASUM)) {
794 * Now that the inodes are locked, we need to start writeback ourselves
795 * and can not rely on the writeback from the VFS's generic helper
796 * generic_remap_file_range_prep() because:
798 * 1) For compression we must call filemap_fdatawrite_range() range
799 * twice (btrfs_fdatawrite_range() does it for us), and the generic
800 * helper only calls it once;
802 * 2) filemap_fdatawrite_range(), called by the generic helper only
803 * waits for the writeback to complete, i.e. for IO to be done, and
804 * not for the ordered extents to complete. We need to wait for them
805 * to complete so that new file extent items are in the fs tree.
807 if (*len == 0 && !(remap_flags & REMAP_FILE_DEDUP))
808 wb_len = ALIGN(inode_in->i_size, bs) - ALIGN_DOWN(pos_in, bs);
810 wb_len = ALIGN(*len, bs);
813 * Since we don't lock ranges, wait for ongoing lockless dio writes (as
814 * any in progress could create its ordered extents after we wait for
815 * existing ordered extents below).
817 inode_dio_wait(inode_in);
819 inode_dio_wait(inode_out);
822 * Workaround to make sure NOCOW buffered write reach disk as NOCOW.
824 * Btrfs' back references do not have a block level granularity, they
825 * work at the whole extent level.
826 * NOCOW buffered write without data space reserved may not be able
827 * to fall back to CoW due to lack of data space, thus could cause
830 * Here we take a shortcut by flushing the whole inode, so that all
831 * nocow write should reach disk as nocow before we increase the
832 * reference of the extent. We could do better by only flushing NOCOW
833 * data, but that needs extra accounting.
835 * Also we don't need to check ASYNC_EXTENT, as async extent will be
836 * CoWed anyway, not affecting nocow part.
838 ret = filemap_flush(inode_in->i_mapping);
842 ret = btrfs_wait_ordered_range(inode_in, ALIGN_DOWN(pos_in, bs),
846 ret = btrfs_wait_ordered_range(inode_out, ALIGN_DOWN(pos_out, bs),
851 return generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
855 static bool file_sync_write(const struct file *file)
857 if (file->f_flags & (__O_SYNC | O_DSYNC))
859 if (IS_SYNC(file_inode(file)))
865 loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,
866 struct file *dst_file, loff_t destoff, loff_t len,
867 unsigned int remap_flags)
869 struct inode *src_inode = file_inode(src_file);
870 struct inode *dst_inode = file_inode(dst_file);
871 bool same_inode = dst_inode == src_inode;
874 if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
878 btrfs_inode_lock(src_inode, BTRFS_ILOCK_MMAP);
880 lock_two_nondirectories(src_inode, dst_inode);
881 btrfs_double_mmap_lock(src_inode, dst_inode);
884 ret = btrfs_remap_file_range_prep(src_file, off, dst_file, destoff,
886 if (ret < 0 || len == 0)
889 if (remap_flags & REMAP_FILE_DEDUP)
890 ret = btrfs_extent_same(src_inode, off, len, dst_inode, destoff);
892 ret = btrfs_clone_files(dst_file, src_file, off, len, destoff);
896 btrfs_inode_unlock(src_inode, BTRFS_ILOCK_MMAP);
898 btrfs_double_mmap_unlock(src_inode, dst_inode);
899 unlock_two_nondirectories(src_inode, dst_inode);
903 * If either the source or the destination file was opened with O_SYNC,
904 * O_DSYNC or has the S_SYNC attribute, fsync both the destination and
905 * source files/ranges, so that after a successful return (0) followed
906 * by a power failure results in the reflinked data to be readable from
909 if (ret == 0 && len > 0 &&
910 (file_sync_write(src_file) || file_sync_write(dst_file))) {
911 ret = btrfs_sync_file(src_file, off, off + len - 1, 0);
913 ret = btrfs_sync_file(dst_file, destoff,
914 destoff + len - 1, 0);
917 return ret < 0 ? ret : len;